Traditional thickened foodstuffs such as Chef Sauces, soups & gravies are based on starch as a thickening agent. Within the process of preparation, the sauce, soup or gravy is heated such that starch granules are swollen irreversibly and the amylose content of the starch granule is preferentially solubilized. In this way the granule birefringence and crystallinity disappear and a viscous paste is formed. The swollen starch granules, upon cooling, show a strong tendency to associate with each other. This phenomenon is called retrogradation. With traditional chef sauces, the sauce is used shortly after preparation and therefore the natural starches used cause no problem.
However, in manufactured foodstuffs the starch has to survive extremes in terms of processing (i.e. high temperatures and high shear) and then remain stable for long periods of storage time. Storage may be under frozen, chill or ambient conditions. The thickened foodstuff then needs to be stable on re-heating for consumption. The required product stability is not possible using traditional native starch thickened systems. Manufactured sauces have to date solved this problem by one of two solutions;
(a) The addition of gelatin to the native starch thickened foodstuff. This assists in limiting the extent of retrogradation damage. However, gelatin is expensive and comes from an animal source and is therefore unsuitable for vegetable/kosher foods. Furthermore the addition of gelatin does not enable the foodstuff to retain the desired viscosity when subjected to the required processing conditions (high temperatures and high shear).
(b) Use of chemically modified (cross-linked and derivatized) starches.
The use of such modified starches causes a number of problems and concerns such as;
(i) they give a starchy taste and texture, probably due to some (limited) retrogradation on storage PA1 (ii) they are seen by consumers as chemicals; and PA1 (iii) the final sauces are not as smooth a home-made sauces. This is probably due to limited swelling or retrogradation of the starch polymers. PA1 (a) cooking an amylopectin component source in order to gelatinize the starch present; and PA1 (b) subjecting the cooked amylopectin component source to shear forces in order to solubilize the amylopectin component. PA1 (i) preparation of a dispersion comprising the second biopolymer PA1 (ii) mixing the second biopolymer dispersion with the amylose polymer containing component, the temperature of the second biopolymer dispersion during mixing being below the gelatinization temperature of the amylose polymer containing component; PA1 (iii) heating the mixture to a temperature of above the gelatinization temperature of the amylose polymer containing component for sufficient time to substantially gelatinize the amylose polymer containing component; and PA1 (iv) cooling the mixture as required and optionally freezing.
It is therefore desirable to be able to replace modified starch thickening agents in foodstuffs.